3,190 research outputs found
Development of low cost double probe plasma measurement system for a lean satellite HORYU-IV
No full textA lean satellite is equivalent to a small/micro/nano/pico satellite that utilizes untraditional risk-taking development approaches to achieve low-cost and fast-delivery. Lean satellites have demonstrated great ability to be used for the study of space plasma and Earth’s ionosphere which has helped in the prediction of many astrophysical phenomena and forecasting of geophysical changes on ground. Several methods have been employed in the measurement of space plasma parameters over the years using the Langmuir Probe. These methods employed different techniques using single probes or double probes. Single probe requires a well-defined reference which is difficult in small spacecraft. Moreover, high current flow in the saturation mode may destroy the probe and on-board circuitry. A low cost double Langmuir probe made of gold with its measurement circuit has been designed and tested inside RF generated Argon plasma in the pressure of 1.4×10-2 Pa that confirms the electron density from 1010 to 1012 m-3. Important design considerations such as operability of the designed system in low earth orbit grade plasma, mitigation of probe contamination and sputtering of the electrode surface were analysed in the paper to ensure that the developed system can provide high fidelity plasma measurement data throughout the life span of HORYU-IV (Arc Event Generator and Investigator Satellite) which is a 13 kg, 40 cm cubic lean satellite under development at the Kyushu Institute of Technology
Erratum: 3D bioprinted in vitro secondary hyperoxaluria model by mimicking intestinal-oxalatemalabsorption-related kidney stone disease (Applied Physics Reviews (2022) 9 (041408) DOI: 10.1063/5.0087345)
No full text© 2023 Author(s).This article was originally published online on 21 November 2022 with an incorrect affiliation identifier for author Dong-Woo Cho. It is correct as it appears above. All online versions of this article were corrected on 23 November 2022. AIP Publishing apologizes for this error.11Nsciescopu
Unimodality of Betti numbers for Hamiltonian circle actions with index-increasing moment Maps
No full textThe unimodality conjecture posed by Tolman in [L. Jeffrey, T. Holm, Y. Karshon, E. Lerman and E. Meinrenken, Moment maps in various geometries, http://www.birs.ca/workshops/2005/05w5072/report05w5072.pdf] states that if (M,ω) is a 2n-dimensional smooth compact symplectic manifold equipped with a Hamiltonian circle action with only isolated fixed points, then the sequence of Betti numbers {b0(M),b2(M),...,b2n(M)} is unimodal, i.e. bi(M) ≤ bi+2(M) for every i < n. Recently, the author and Kim [Y. Cho and M. Kim, Unimodality of the Betti numbers for Hamiltonian circle action with isolated fixed points, Math. Res. Lett. 21(4) (2014) 691-696] proved that the unimodality holds in eight-dimensional case by using equivariant cohomology theory. In this paper, we generalize the idea in [Y. Cho and M. Kim, Unimodality of the Betti numbers for Hamiltonian circle action with isolated fixed points, Math. Res. Lett. 21(4) (2014) 691-696] to an arbitrary dimensional case. We prove the conjecture in arbitrary dimension under the assumption that the moment map H : M → R is index-increasing, which means that ind(p) < ind(q) implies H(p) < H(q) for every pair of critical points p and q of H, where ind(p) is the Morse index of p with respect to H. © World Scientific Publishing Company1111sciescopu
Mejora de la Fuerza de Arrastre por Colisión de Iones en el Panel Conductivo de Alta Tensión en un Cubesat
No full textHoy en día, hay una gran explosión para lanzar los nanosatélites a la órbita terrestre baja (LEO) ya que pueden ser fabricados fácilmente por universidades o empresas. No es asi requerido tanto dinero para probar y hacer experimentos en el espacio con fines científicos que muchas universidades están muy interesadas en construir nanosatélites para probar y probar nuevos científicos equipo. Sin embargo, esta relativa accesibilidad abierta para poner en órbita cualquier nanosatélites tenía aumento de los desechos espaciales que ahora se considera un gran problema para futuras misiones al espacio.
Las agencias de la Organización y del Espacio intentaron mitigar este efecto irreversible haciendo algunos requisitos y especificaciones para que los nanosatélites los conviertan en desorbitado más rápido y disminuyan la basura en el espacio.
El propósito de esta tesis es proporcionar otra fuerza de arrastre, que en realidad está actuando en todos satélites, para hacerlos decaer más rápido en la Tierra. Los satélites en el espacio están en plasma medio ambiente, que son básicamente iones y electrones que se mueven aleatoriamente en el espacio. Los la interacción entre satélite y plasma se basa en iones, que son mucho más pesados que electrón. Cuando los iones colisionan en la superficie del satélite, producen cierta fuerza debido a la cambio de impulso, sin embargo, este valor de intercambio de momento es demasiado pequeño y es considérelo como una fuerza despreciable para calcular el tiempo de deorbitación. Esta tesis se centra principalmente en polarizando una superficie conductora en la nave espacial, mejorará la fuerza del plasma y hará satélites decaer más rápido en la Tierra.Tesi
Comparison of Thermal Design of Horyu-Series and Results of Thermal Vacuum Testing
No full textJapanViet NamKyushu Institute of TechnologyVNSC107ICES107: Thermal Design of Microsatellites, Nanosatellites, and PicosatellitesVienna, AustriaHirokazu Masui, Kyushu Institute of Technology, JapanThe 46th International Conference on Environmental Systems was held in Vienna, Austria, USA on 10 July 2016 through 14 July 2016.Mengu Cho, Kyushu Institute of Technology, JapanTakashi Yamasaki, Kyushu Institute of Technology, JapanThin Tang Long, Vietnam National Space Center (VNSC), VietnamThis paper describes the thermal design and testing of Horyu-4 to be launched in 2016. Kyushu Institute of Technology (KIT) has been developing nano-satellite since 2006. 2 nano-satellites (Horyu-2) and Shinen-2)) have been launched so far. In 2016, Horyu-4 will be launched by JAXA H2A rocket. Horyu-4 satellite project was started from 2013 and a basic design of Horyu-4 is based on that of Horyu-2 launched in 2012. Horyu-4 is 30cm-cube satellite and its weight is 12 kg. A main mission of Horyu-4 is observation of discharge phenomena on solar cell in space. Main changes from Horyu-2 are (1) increasing in weight with increasing mounted mission components, (2) changing of orbit inclination from 98.1˚ to 51.6˚, and (3) changing of orbit altitude from 680 km to 575 km. The different point in a thermal design of Horyu-2 and 4 from a conventional nano and micro-satellite is a wide temperature fluctuation due to low density. Horyu-4 adopts a passive thermal control. Surface properties of external panels and insulation between internal circuit boards and structure frames were adjusted to ensure acceptable temperature ranges including margin for internal circuit boards. To verify the thermal design and operation of bas system and components, thermal vacuum tests were conducted in each development phase.
This paper will explain the detail of Horyu-4’s thermal design comparing with Horyu-2’s design and on-orbit data. In addition, results and testing method for thermal vacuum testing will be reported. Finally, flight prediction data and on-orbit data will be compared
Systems biology for reverse aging
No full textCellular senescence is an irreversible and permanent cell cycle arrest in response to internal and external stresses. Its unresponsiveness to growth factor signals distinguishes it from a potentially reversible state, quiescence. Cellular senescence can inhibit tumor development by blocking proliferation of damaged cells, but as senescent cells become accumulated in a tissue, they can contribute to the promotion of agerelated diseases such as cancer by secreting inflammatory cytokines [1]. © 2021 Cho et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
The antihypertensive effects of the Jamaican Cho-Cho (Sechium edule)
No full textThe experiments reported in this study constitute a preliminary investigation into the possible hypotensive effect of the Jamaican Cho-Cho (Sechium edule). Experiments were conducted in a random and blind fashion on two sub species of Sechium edule. Both the pulp and the peel were examined for hypotensive activity. Water-soluble extracts were prepared from these components of the fruit and injected into anaesthetised rats. Various cardiovascular parameters were measured including heart rate, mean arterial pressure (MAP) and several ECG intervals. We report that all extracts tested produced a fall in blood pressure with little change in ECG intervals. Extract B produced the least change in heart rate with a fall in MAP of approximately 23 mmHg. Changes in heart rate with all extracts appeared to be minimal as an ED25 value could only be determined for extract A, and ED10 values could not be evaluated for extracts C and D. The mechanism(s) by which these extracts produce their hypotensive effects could not be determined in these preliminary experiments. However, it appears not to involve direct effects on cardiac tissue. This conclusion is based on the finding that it took a minimum of 10 to 15 seconds for the hypotensive action to manifest post bolus. Future experiments will be aimed at delineating the mechanism(s) involved in decreasing MAP.Peer reviewedfinal article publishe
Nota su Eschilo, Cho. 65
No full textThe author defends the reading ἄκραντος in the sense of “unfinished” in Aesch. Cho. 65
An ‘omics approach towards CHO cell engineering
No full textBiotechnology and Bioengineering, 110, 1255–1271Note : if this item contains full text it may be a preprint, author manuscript, or a Gold OA copy that permits redistribution with a license such as CC BY. The final version is available through the publisher’s platform.Chinese hamster ovarian cells (CHO) cells have been extensively utilized for industrial production of biopharmaceutical products, such as monoclonal antibodies, human growth hormones, cytokines, and blood-products. Recent advances in recombinant DNA technology have resulted in the bioengineering of CHO cells that have robust gene amplification systems and can also be adapted to grow in suspension cultures. In parallel, recent advances in techniques and tools for decoding the CHO cell genome, transcriptome, proteome, and glycome have led to new areas of study for better understanding the metabolic pathways in CHO cells with the long-term goal of developing new biologics. This review paper discusses the recent advances in bioengineering strategies in CHO cell lines and the impact of the knowledge gained by CHO cell genomics, transcriptomics, and glycomics on the future of CHO-cell engineering.National Institute of General Medical Scienceshttps://login.libproxy.rpi.edu/login?url=https://doi.org/10.1002/bit.2484
Considering spurious timeout in proxy for improving TCP performance in wireless networks
No full textIn this paper, we introduce a new proxy that effectively prevents unnecessary retransmissions of Transmission Control Protocol data segments from flowing over a wireless link on a path with sudden delay. The proposed Spurious Timeout Detection (STD) algorithm detects spurious timeout based on the data and acknowledge sequence number. It responses to spurious timeout by filtering unnecessary data transmissions that can cause spurious fast retransmission. Simulation result shows that proposed STD algorithm performs better than, or as well as, other end-to-end mechanisms in a certain range of data rate. (C) 2003 Published by Elsevier B.V.
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